This invention relates generally to patching devices for use in the telecommunications field. More particularly, this invention relates to devices for accessing, monitoring, testing and patching of telecommunication circuits wherein the devices comprise discrete pre-emptive patching modules which are easily snap fit onto a suitable panel.
Modular jack distribution systems allow standard 25 pair (50 pin) telephone connectors (Telco) cabeling systems to be redistributed for multiple modular jack access. These devices allow efficient break-out, interconnection and patching for modems, terminals, CPU's and the like. In particular, panel systems of this type provide quick and efficient means for monitoring, isolating, testing and patching of four, six and eight wire communications circuits.
Patching devices for telecommunications signalling applications have been in use for many years. The earliest widespread use of patch connectors for signalling circuits consisted of "Bantam" jack fields: plugs with a single probe element consisting of a series of aligned but electrically isolated cylindrical conductors designed to mate with appropriately spaced contact spring fingers in a female receptacle with a circular opening. The receptacle spring fingers are configured many ways including those with switchable connections activated by the insertion of the cylindrical plug. Electrical schematics for various prior art Bantam jack configurations are described in "DSX Digital Signal Cross-Connect", Catalogue No. 218 9/86, pp. 54-55 published by ADC Telecommunications, Minneapolis, Minn. Although Bantam jacks are still in use for signal applications between telephone company central office facilities, their cost and physical limitations with respect to ease of cable and patch cord terminations (wrapped wire and solder terminals) and a maximum of only two switchable connection points per connector have inhibited their acceptance and use for commercial and industrial wiring applications. Also, because temporary shorts occur between tip and ring conductors as the plug is inserted, Bantam connectors present an electrical hazard to some types of voltage sensitive equipment. Instead, the connector of choice for administering patching functions for private data and voice communications networks operating over unshielded twisted pair wiring are the well known modular jack connectors used for residential and commercial telephone outlets.
Installations with modular jack patching are most commonly comprised of two sets of patch panels; one set wired directly to equipment or backbone cables which service broad areas of the network and another set connected to horizontal wiring (individual cables extending to each work area outlet). Connections between horizontal wiring and the network equipment are made via patch cords that bridge the two sets of jack fields. Although this wiring scheme is one of the most common methods for accessing, monitoring, testing and patching unshielded twisted pair telecommunications circuits, it has several disadvantages with respect to cost, ease of use and appearance. First, because this method requires two physically separate jack fields, the user is forced to purchase two separate jack connectors and a patch cord along with associated wire termination and mounting hardware for each active node (network access point). Second, the requirement of a patch cord for each node leads to problems with wire management, transmission integrity and the administration of adds, moves and changes. For example, provisions must be taken into account for the physical loading and space requirements of the many patch cords required for large commercial installations. Administration ease is further reduced by large numbers of patch cords because they inhibit the ability to trace port to port connections and obscure circuit identification markings on the front surface of the patch panels.
In addition, the appearance of conventional patch field installations often lacks any semblance of order or organization due to the quantity of cords required for a completed installation. When network moves or changes are made, incidental contact with other patch cords can cause movement of jack/plug connections which degrade transmission integrity.
One other limitation of the prior art modular jack based patching method is that there is no inherent physical relation between the input and output jacks. The physical separation of the two jack fields restricts the ability to modify patch hardware to include application specific wiring or circuitry between input and output jacks that may facilitate installation and functional adaptations that often accompany advanced networking installations such as ISDN. Bantam jack schematics shown in the above-referenced ADC Telecommunications catalogue are examples of application specific jack configurations, many of which require circuit elements and switching features that extend beyond the capabilities of conventional modular jack patch panels.
The present invention utilizes a method for reversibly interrupting patched connections between contact elements similar to prior art jack designs with internally bussed contact positions. A good example of such a device is a standard modular jack interface known in the industry as a type RJ31X modular jack which, when unmated, provides bridged connections between jack positions 1 and 4 and positions 5 and 8. When a standard modular plug is mated with the jack, the aforementioned bridged connections are reversibly interrupted. An illustration of this type of bussed jack arrangement is shown in U.S. Pat. No. 4,944,698 assigned to the assignee hereof. A major limitation of this type of prior art jack configuration is that there is no allowance for the use of intrajack bridging elements for interruptable interjack circuit schemes that permit independent access to bridged jack contact elements. Nor do they allow for the introduction of circuit elements in series or in parallel with bridged (or patched) connections.